I was having the same problem with a Pro Hunter and a 7mm Rem Mag barrel. I was getting 3.5" to 4" groups @ 100 yards. Tried all different things to no avail. Posted to this forum and Davemuzz responded with his corrective action. I couldn't find any longer forearm screws and was going to order some from Brownell's when I came across this add in the "One Good Shot", The TC Collectors Association Quarterly publication. Logged on to "strattoncustom.com" and read about the barrel hangers Steve makes. I ordered one and when I received it, I realized the forearm had to be altered. Sent the forearm to him and had him inlet it to the hanger. I have only been able to get to the range once, but my groups shrank to about one inch for five shots. What's nice is that as long as the barrel contour is the same, the forearm can be used on different barrels. I just ordered another hanger for my 204 Ruger barrel and leave the hangers on the barrel. I just didn't have the time to convert my forearm like Davemuzz, but if I had, I feel certain it would have worked as his did. For some reason, the Pro Hunter is the only TC rifle that I have had these problems with. My regular Encore barrels and Contender rifle barrels have all given me good accuracy. By the way, Steve Stratton was formerly associated with Virgin Valley Arms which was the predesessor to Match Grade Machine. Good luck and don't give up on your barrels!
DeBois